1. Field of the Invention
The present invention relates to a fuel cell stack including a stack body formed by stacking power generation cells in a stacking direction, and terminal plates, insulating members, and end plates provided at both ends of the stack body in the stacking direction. Each of the power generation cells includes a membrane electrode assembly and a separator. The membrane electrode assembly includes a pair of electrodes and an electrolyte interposed between the electrodes.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell employs a solid polymer electrolyte membrane. The solid polymer electrolyte membrane is a polymer ion exchange membrane. In the fuel cell, the solid polymer electrolyte membrane is interposed between an anode and a cathode each including an electrode catalyst layer of electrode catalyst and a gas diffusion layer of porous carbon to form a membrane electrode assembly (MEA). The membrane electrode assembly is sandwiched between separators (bipolar plates) to form a power generation cell. A predetermined number of the power generation cells are stacked together to form a fuel cell stack, e.g., mounted in a vehicle.
In some of power generation cells of such a fuel cell stack, in comparison with the other power generation cells, the temperature is decreased easily due to heat radiation to the outside. For example, in the power generation cells provided at ends of the fuel cell stack in the stacking direction (hereinafter also referred to as the “end power generation cells”), since a large amount of the heat is radiated to the outside, e.g., from the terminal plates and/or the end plates, or the like, the decrease in the temperature is significant.
In this regard, for example, a fuel cell stack disclosed in Japanese Laid-Open Patent Publication No. 2009-277521 (hereinafter referred to as conventional technique) is known. As shown in FIG. 6, the fuel cell stack includes a stack body 1 formed by stacking a plurality of unit cells, a pair of current collecting plates 2a, 2c provided on both sides of the stack body 1, a pair of end plates 3a, 3c provided outside the current collecting plates 2a, 2c, a plurality of elastic members 4 provided outside the current collecting plates 2a, 2c to apply pressure to components between the current collecting plates 2a, 2c, and heat insulating members 5 provided around the elastic members 4 to cover the elastic members 4.